The present invention relates to electronic data storage and electronic data storage devices. More particularly, the present invention relates to a system and method of storing write data in electronic memory (e.g., flash memory).
Electronic memory may be defined as the working space used by a computer to hold programs and data. One type of electronic memory is physical memory (e.g., data storage that comes in the form of chips). Generally, electronic memory may be thought of as an array of boxes, each of which is capable of holding a single byte of information. This type of memory may come in the form of an electronic device capable of storing information as binary data. The number of bytes referring to memory reflects the number of very low level logical states that can be stored in a memory device.
Electronic memory comes in a variety of forms and may serve a number of purposes. For example, flash memory is a type of electronic memory that may be used to facilitate fast information storage in computer devices (e.g., digital cameras, video game consoles, and personal computers). Computer BIOS chips, memory sticks, PCMCIA cards, and so forth are examples of flash memory devices. In operation, flash memory devices generally perform more as hard drives than as RAM. In fact, flash memory devices may be considered solid state (i.e., electronic instead of mechanical or magnetic) storage devices. Further, flash memory devices are typically considered reliable, cost-effective devices for programmable, nonvolatile data storage. Indeed, once programmed, flash memory devices tend to be extremely reliable and are generally nonvolatile (i.e., do not require power to retain their programmed states and will not necessarily have data loss upon loss of power).
A flash memory device can be erased by moving electrons disposed in cells of the flash memory device such that the cells are returned to a normal state (e.g., having a value of 1 instead of 0). This may be achieved by the application of an electric field. For example, a flash memory chip may be erased by the application of an electric field to the entire chip or to a section of the chip. Because flash memory devices can be erased entirely or in sections, it may be faster to erase flash memory than to erase the memory of traditional memory devices. Indeed, the entire memory or predetermined sections of the memory (i.e., blocks or sectors) in a flash memory device may be erased at one time, as opposed to erasing or overwriting one byte at a time in other types of memory devices. This is typically done in flash memory devices using in-circuit wiring to apply an electric field either to the entire chip or to a particular sector. However, while a flash memory device may be erased faster than traditional memory devices, it should be noted that it is still inherently slow to erase and write. Indeed, even a single erase/write cycle can noticeably degrade a system's performance.
Once a flash memory chip or sector has been erased, it can be rewritten. Because flash memory devices are either entirely erased or erased in large blocks (e.g., sectors), when data is being modified on a flash memory device, the data is often transferred during modification. For example, data from the flash memory device is usually transferred to RAM, the flash memory is erased, the data is modified, and then the modified data is written from RAM to the flash memory device. While flash memory devices are generally reliable once programmed, data may be corrupted during such a process. What is needed is an improved electronic memory device that is more reliable, robust, and flexible.